Showing papers by "University of Oviedo published in 1987"
TL;DR: A new method based on the simultaneous action of Safranin and Alcian Blue (or green) is reported, its main advantages are its simplicity and the absence of differentiation processes.
Abstract: SUMMARY
A new method based on the simultaneous action of Safranin and Alcian Blue (or green) is reported The main advantages of this method are its simplicity and the absence of differentiation processes Free-hand, frozen and paraffin sections can be stained with this technique Sections are placed in 10% sodium hypochlorite for 1–5 min, rinsed in 5% acetic acid and stained for 10 min Sections are then washed in distilled water for 1 min, rinsed in distilled water for 5 min and mounted
115 citations
21 Jun 1987
TL;DR: In this paper, the influence of the tapped inductor turn ratio (λ) is analyzed in dc-to-dc converters derived from buck, boost and buck-boost topologies.
Abstract: Six different topologies of tapped-inductor dc-to-dc converters derived from buck, boost and buck-boost topologies are analyzed. Both dc and ac analysis in continuous and discontinuous operating modes are considered. The influence of the tapped inductor turn ratio (λ) is very important in the circuit behaviour. Particulary in the poles and zeros distribution of the transfer function. Some important conclusions about the dynamical characteristics of converters are derived from this study. Theoretical results are compared with those obtained from experiment carried out on some prototypes. Generalized conclusions are presented considering classical buck, boost and buck-boost (non tapped-inductor) as a particular case of these converters.
90 citations
TL;DR: Shells of the brachiopod Anathyris phalaena (Phillips) from the Raneces Group (Emsian) of NW Spain are frequently encrusted by epizoans including Aulopora, Hederella, Spirorbis and trepostome bryozoans.
76 citations
TL;DR: In this paper, the authors used the asymmetric equations proposed by Scatchard, Toop, and Hillert to predict ternary excess enthalpies from the three binary mixtures involved.
Abstract: Methods for predicting ternary excess enthalpies from excess enthalpy data for the three binary mixtures involved are examined and tested for forty-two sets of ternary data. In order to study the relation between the performance of the methods and the characteristics of the components in the mixture, the sets of data were classified into four groups according to the chemical nature of their components. The asymmetric equations proposed by Scatchard, Toop, and Hillert are shown to provide accurate predictions. The ratio of the standard deviations between experimental and predicted excess enthalpies and the maximum absolute value of this magnitude is 0.05 or less for most of the systems. These equations are asymmetric with respect to the numbering of components. A rule is given for selecting which component is to be designated as component 1 for systems showing endothermic mixing, exothermic mixing, or a combination of endothermic and exothermic mixing. Correlation methods are also examined and a partial differential approximant is proposed to represent the ternary contribution to the excess enthalpy.
59 citations
TL;DR: From results obtained by addition of glucose to yeast cultures at pH 7.5 it was concluded that others factors than cAMP can play a role in the catabolite inactivation mechanism of both enzymes.
Abstract: A reversible carbon catabolite inactivation step is described for isocitrate lyase from Saccharomyces cerevisiae. This reversible inactivation step of isocitrate lyase is similar to that described for fructose 1,6-bisphosphatase. Addition of 2,4-dinitrophenol, nystatin or glucose to cultures, grown in ethanol as carbon source, caused a rapid loss of the isocitrate lyase and fructose 1,6-bisphosphatase activities at pH 5.5 but not at pH 7.5. These results suggest that intracellular acidification and thus a cAMP increase is involved in the catabolite inactivation mechanism of both enzymes. From results obtained by addition of glucose to yeast cultures at pH 7.5 it was concluded that others factors than cAMP can play a role in the catabolite inactivation mechanism of both enzymes.
51 citations
TL;DR: The purpose of this study was to establish the range of total serum IgE in a healthy population lacking personal and family history of allergy, as well as the influence of genetic factors, environmental factors, age, and sex on the serum Ig E levels.
Abstract: The purpose of this study was to establish the range of total serum IgE in a healthy population lacking personal and family history of allergy, as well as the influence of genetic factors (family history of allergy), environmental factors (degree of air pollution), age, and sex on the serum IgE levels. Using a commercial enzyme immunoassay (Phadezym IgE Prist) the mean serum level of IgE was determined in 363 non-atopic children from 0 to 12 years of age. The geometric mean of serum IgE increased according to age, indicating a positive correlation between both. Higher mean values of serum IgE were found for children with a family history of allergy, than for children without (27.82 and 14.49 U/ml respectively). The percentage of variation due to age was about 94.5% in children with no family history of allergy. The mean value of serum IgE increased with the degree of air pollution in the living area (15.49 U/ml in non-polluted areas, 20.78 U/ml in very polluted areas). However, the influence of air pollution was smaller than the influence of family history on the mean values of serum IgE. The mean value of serum IgE was not modified by sex.
46 citations
TL;DR: The overall mortality rate was 25.4%, and the factors associated with a poor prognosis were age over 60 years, lack of adequate surgical treatment, severe underlying disease, metastatic foci, and polymicrobial and/or nosocomial infection.
Abstract: Anaerobic bacteremia (116 cases) represented 5.4% of the total cases of bacteremia in the Hospital Nuestra Sefiora de Covadonga of Oviedo, Spain, during a five-year period (1981-1985). Microbiologic data for all 116 cases and clinical data for 63 patients were analyzed. A total of 129 isolates were identified as gram-negative bacilli (45.7%), grampositive bacilli (38.0%), gram-positive cocci (14.0%), and gram-negative cocci (2.3%). Bacteroidesfragilis and Clostridium perfringens were the most frequently occurring species. Anaerobic polymicrobial infection was detected in 21 patients. The most relevant clinical features were fever (79%), metastatic abscesses (33%), anemia (27%), septic shock (25%), and disseminated intravascular coagulation (6%). The overall mortality rate was 25.4%, and the factors associated with a poor prognosis were age over 60 years, lack of adequate surgical treatment, severe underlying disease, metastatic foci, and polymicrobial and/or nosocomial infection. Anaerobic bacteria constitute the vast bulk of the endogenous microflora of the human gastrointestinal tract [1]. Although they have not been considered a significant cause of infectious disease, advances in the techniques of anaerobic bacteriology have been accompanied by an increasing awareness of the pathogenicity of these organisms [2-5]. At present the incidence of hospital bacteremia reported
46 citations
TL;DR: In this article, the effect of some surfactants present in the medium on the adsorbed folic acid stripping signal is studied. But the effect is limited to the presence of a 700fold excess of gelatin.
44 citations
TL;DR: In this article, a new type of two-output dc-dc converter is proposed, where two completely regulated outputs can be obtained using only one switching element and very often without an extra transformer.
Abstract: A new type of two-output dc-dc converter is proposed With this ``double converter'' two completely regulated outputs can be obtained using only one switching element and very often without an extra transformer The operating principle is based on the discontinuous-conduction-mode operation of one output and the continuous-conduction-mode operation of the other output Both outputs are sensed, and the duty cycle of the switching element and the switching frequency are controlled at the same time A prototype has been built, and the results obtained are discussed
40 citations
TL;DR: In a cross-section through the southern arm of the Cantabrian Zone, several duplexes have been identified below the Esla Nappe, which is the uppermost and main thrust sheet of the area.
39 citations
TL;DR: In this article, N -Arylphospha-λ 5 -azenes (1) and (3) were reduced with LiAlH 4 to phosphine derivatives, and the addition of ethyl azidoformate to β-enaminophosphine (4) followed by heating at 150°C yielded 1,3,4-diaza-λ5 -phosphinine derivatives.
TL;DR: An empirical correlation for estimating diffusivities of gases in non-electrolytes at 25°C has been developed in this article, where the solute-solvent diffusivity has been correlated as a function of the solutes and solvent molar volumes at their normal boiling point and the solvent viscosity.
Abstract: An empirical correlation for estimating diffusivities of gases in non-electrolytes at 25°C has been developed. The solute-solvent diffusivity has been correlated as a function of the solute and solvent molar volumes at their normal boiling point and the solvent viscosity. The temperature dependence is expressed by a second equation of the Arrhenius type. The proposed expression, in spite of its simplicity, predicts diffusivities with similar or better accuracy than the equations used for comparison. A nomograph based on the two proposed equations has been constructed.
TL;DR: This is the first report of protoplast isolation from leaves of hazelnut, walnut, sweet cherry, sour cherry and the common pear.
TL;DR: As pupation progressed in the vials, larvae tended to pupate lower and lower, possibly as a response to diminishing levels of humidity inside the vial, which suggests a strong negative correlation between larval developmental time and pupation height.
Abstract: Several lines ofDrosophila simulans andD. melanogaster of different origin were examined for pupation height. In all lines male larvae pupated, on average, higher than females. The pupation heights of early-, intermediate-, and late-pupating larvae were also recorded. As pupation progressed in the vials, larvae tended to pupate lower and lower, possibly as a response to diminishing levels of humidity inside the vials, which suggests a strong negative correlation between larval developmental time and pupation height. Thus, selection experiments for pupation height may also select for developmental rate. Since females generally pupate later than males, larval sex differences in pupation height may reflect sex differences in duration of development. The joint effects of sex and duration of development upon pupation height are discussed in relation to the lack of response previously reported in some experiments selecting for pupation height.
TL;DR: In this paper, the electrochemical behavior of dacarbazine was investigated by Tast and differential pulse polarography (d.p.) at the dropping mercury electrode, by cyclic and differential pulses voltammetry at the hanging mercury drop electrode and by anodic voltammetric at the glassy carbon electrode.
Journal Article•
TL;DR: Dyskeratosis was observed in 12 cases, half of which degenerated, this being the group of worst prognosis, and malignant degeneration was seen in nine of them (10.3%).
Abstract: Eighty-seven precancerous lesions of the larynx were studied; 46 showed keratosis, 31 slight dysplasias, five severe dysplasias, and five carcinomas in situ. The average follow-up was 3.8 years per patient, and malignant degeneration was observed in nine of them (10.3%). This arose on a pre-existing dysplasia in eight cases, and in the other on a hyperkeratosis. Dyskeratosis was observed in 12 cases, half of which degenerated, this being the group of worst prognosis.
TL;DR: The first edrioasteroid to be discovered from the Iberian Peninsula is reported from the Emsian (late Lower Devonian) of the north Spanish coast and it belongs to the species Krama devonica but is unusual in being a mirror image form.
Abstract: The first edrioasteroid to be discovered from the Iberian Peninsula is reported from the Emsian (late Lower Devonian) of the north Spanish coast. It belongs to the species Krama devonica (Bassler) but is unusual in being a mirror image form. This is interpreted as the product of situs inversus during larval development whereby the coeloms on the right side rather than the left side of the bilateral larva have given rise to the definitive adult structures. Thus the hydropore lies in its mirror image position vis-a-vis the anterior/posterior axis and this axis must be homologous with Loven's symmetry plane in echinoids. The phylogenetic position of Krama is analysed cladistically and, by combining this with available stratigraphical information, the most parsimonious phylogenetic tree is produced for the subfamily Agelacrinitinae.
TL;DR: It appears that brush border membranes contain high levels of regulatory subunits of adenylyl cyclase in the absence of catalytic subunits, which represents a previously unrecognized feature of this transduction system that presumably plays an important role in the derangement of intestinal cell function by cholera toxin.
Abstract: Cholera toxin alters intestinal function by stimulation of adenylyl cyclase [ATP pyrophosphate-lyase (cyclizing) or adenylate cyclase, EC 4.6.1.1]. The mechanism of this activation is unknown and particularly puzzling because adenylyl cyclase is confined to the basal lateral membrane of enterocytes, whereas it is the brush border membrane that binds the toxin and contains proteins that undergo cholera toxin-catalyzed ADP ribosylation. It is shown that cholate extracts from cholera toxin-treated brush border membranes can efficiently reconstitute adenylyl cyclase activity in the guanine nucleotide-binding regulatory component (Gs)-deficient cyc- variant of the S49 mouse lymphoma cell line (cyc- cells lack the alpha subunit of Gs needed to activate the catalytic subunit of adenylyl cyclase). Moreover, NaF (in the presence of Al3+) and guanyl-5'-yl imidodiphosphate mediate strong activation of cyc- adenylyl cyclase provided the cholate extracts of brush border membranes are also present. Therefore, it appears that brush border membranes contain high levels of regulatory subunits of adenylyl cyclase in the absence of catalytic subunits. This represents a previously unrecognized feature of this transduction system that presumably plays an important role in the derangement of intestinal cell function by cholera toxin.
TL;DR: In this article, a reversed phase high-pressure liquid chromatographic method is presented for the simultaneous separation and determination of malic, citric, lactic, succinic and ascorbic acids in apple juices and ciders.
Abstract: A reversed-phase high-pressure liquid chromatographic method is presented for the simultaneous separation and determination of malic, citric, lactic, succinic and ascorbic acids in apple juices and ciders. After filtration and/or degasification, the organic acids in the sample are separated on a LiChrosorb/C18 column and quantified by using a rapid diode array detector. The method is considered to be a suitable choice for the accurate and precise determination (C.V. 5%) of these compounds.
TL;DR: In this article, a cyclo-condensation of phosphine imides in the presence of base base was used to synthesize benz-azaphosphininones (BZPNs).
TL;DR: In this paper, a β-acylvinyl anion equivalent with different electrophilic reagents (H 2 O O, D 2 O, Me 3 SiCl, Me 2 S 2, Mel, CH 2 =CHCH 2 Br, Bu i CHO, PhCHO, PhCOCl, Ac 2 O) affords the corresponding functionalized compounds.
TL;DR: While S. albus G took up oleandomycin, S. antibioticus showed a decreased permeability to the antibiotic, suggesting a role for cell permeability in self-resistance.
Abstract: SUMMARY: Resistance to oleandomycin in Streptomyces antibioticus, the producer organism, was studied. The organism was highly resistant in vivo to the antibiotic but sensitive to other macrolides and lincosamides. Protein synthesis in vivo by mycelium of S. antibioticus was more resistant to oleandomycin than that by mycelium of Streptomyces albus G, an oleandomycin-sensitive strain, and this resistance was dependent on the age of the culture, older mycelium of S. antibioticus being more resistant to oleandomycin than young mycelium. [3H]Oleandomycin was capable of binding to the same extent to the 50S subunits of the ribosomes of both organisms. Oleandomycin also inhibited in vitro protein synthesis by ribosomes obtained from an oleandomycin-production medium at the time when maximum levels of oleandomycin were being produced. A clear difference between the ability of the two organisms to incorporate exogenous oleandomycin was observed. Thus, while S. albus G took up oleandomycin, S. antibioticus showed a decreased permeability to the antibiotic, suggesting a role for cell permeability in self-resistance.
TL;DR: The results suggest that this method can be an accurate economic route to crystal calculations of the spin-orbit constants within any cluster-model approach involving the Hamiltonian of Misetich and Buch.
Abstract: We present an approximate method for obtaining spin-orbit coupling constants of 3d atoms and ions from an effective one-body Hamiltonian. The method, suggested by numerical results of the analytical theory of Blume and Watson [Proc. R. Soc. London, Sect. A 270, 127 (1962); 271, 565 (1963)], incorporates the model potential approach of Bonifacic and Huzinaga [J. Chem. Phys. 60, 167 (1974)] for representing the core-valence interactions. In combination with reduced valence basis set, the new procedure gives accurate spin-orbit constants for the 3d atoms, and slightly less accurate values for di- and tripositive 3d ions. These results suggest that this method can be an accurate economic route to crystal calculations of the spin-orbit constants within any cluster-model approach involving the Hamiltonian of Misetich and Buch [J. Chem. Phys. 41, 2524 (1964)].
TL;DR: The lymph nodes of 32 patients operated on for carcinomas of the larynx and pharynx, were evaluated for the pattern of lymph node response and well-differentiated carcinomas predominated in patterns 1 and 2, whereas moderately and poorly differentiatedpredominated in pattern 3.
Abstract: The lymph nodes of 32 patients operated on for carcinomas of the larynx and pharynx, were evaluated for the pattern of lymph node response. Pattern 1 (predominantly lymphocytes) and pattern 2 (predominantly germinal centres) showed a fewer number of nodal metastases than pattern 3 (non-stimulated nodes). Well-differentiated carcinomas predominated in patterns 1 and 2, whereas moderately and poorly differentiated predominated in pattern 3. Patterns 1 and 2 predominated in clinical stages I-III, and pattern 3 in stage IV. The survival decreased progressively from pattern 1 to pattern 3.
TL;DR: In this article, a cluster-in-vacuo calculation for the CrFn−b (n = 2-5) systems at several metal-ligand distances is reported.
TL;DR: In this article, the frozen-core calculations on the (He) 2s22p6-1S state of the F− ion and the (Ar) 3d44s2-5D state of Cr atom, obtained with differently reduced basis sets and different core-projection schemes, are presented and compared with the corresponding all-electron results in order to analyze the behavior of the core projection under these circumstances.
Abstract: Frozen-core calculations on the (He) 2s22p6 – 1S state of the F− ion and the (Ar) 3d44s2 – 5D state of the Cr atom, obtained with differently reduced basis sets and different core-projection schemes, are presented and compared with the corresponding all-electron results in order to analyze the behavior of the core projection under these circumstances. Severe truncation of the valence basis set can give frozen-core results noticeably deviated from the all electron values if the regular projection (projection factors xg = 2.0) is adopted. Much better results are obtained in these cases if a softer projection (xg = 1.0) is used for those core orbitals having high electronic density in regions where the valence basis set has low flexibility. In these circumstances the expectation value of the core projector becomes a nonvanishing correction to the valence energy because the core-valence orthogonality is incomplete after core projection.
TL;DR: In this paper, the principal variables involved in the salt crystallisation test are reviewed: concentration of the solution, type of immersion, temperature and time of drying of the specimens, etc.; as well as the criteria used in the evaluation of induced damages.
Abstract: The salt crystallisation test is, for its simplicity and aggressivity, one of the most suitable ageing tests to evaluate the durability of rock materials. However the results of this test could be conditioned by differences in their experimental procedure.
In this article the principal variables involved in the salt crystallisation test are reviewed: concentration of the solution, type of immersion, temperature and time of drying of the specimens, etc.; as well as the criteria used in the evaluation of induced damages.
The knowledge and control of these factors facilitates the optimization of the test, and the correct interpretation of the obtained data.
TL;DR: In this article, the authors describe minute, lamellose concentric micro-frills on the external surfaces of the Devonian brachiopod Athyris campomanesi (Verneuil & Archiac).
Abstract: Minute, lamellose concentric micro-frills are described on the external surfaces of the Devonian brachiopod Athyris campomanesi (Verneuil & Archiac). The micro-frills are very regularly spaced with a separation of approximately 0.5 mm, are inclined anteriorly and antero-laterally, and become more or less recurved peripherally down towards the valve surface. These micro-frills must have been secreted by outward extensions of epithelium, presumably resulting from an increase in the rate of cell proliferation or extension in the marginal zone. Extrapolating from the known growth rates of living brachiopods, it seems probable that the micro-frills formed very rapidly, within a matter of days or hours. In life the micro-frills would have formed minute channels around the peripheries of both valves, similar in form and function to rain gutters. As such they probably functioned as baffle chambers, within which excess paniculate material from the inhalant feeding currents would have accumulated. Such particulate material is likely to have been moved laterally from the median axis of the shell down to the sediment surface under the effects of gravity and in vitro shell movements. Each micro-frill may only have functioned in this fashion for a matter of weeks before being rendered ineffective by the forward growth of the valve margin, at which stage it would have been abandoned and replaced by a subsequently formed micro-frill.
TL;DR: In this paper, the Hartree-Fock-Roothaan calculations on the octahedral CrF 5−6 cluster with the Cr + F − distance have been obtained.
TL;DR: A simple method for the simultaneous staining of nerve cells and fibers, applicable to sections of pieces embedded in methacrylate, is described.
Abstract: A simple method for the simultaneous staining of nerve cells and fibers, applicable to sections of pieces embedded in methacrylate, is described. Sections of 12 micron in thickness were attached to slides and stained for 10-18 hours in the following solution: 0.03% thionin, 0.5% formaldehyde, 0.5% acetic acid in distilled water. They were then rinsed in acetic water (0.5% acetic acid) for 30 seconds, washed in distilled water, dehydrated through 96% and absolute ethanol, cleared in eucalyptol, and mounted in Eukitt.